Method of working electric resistance welding machines operating with continuous current



E. SCHRUDER.

.METHOD OF WORKING ELECTRIC RESISTANCE WELDING MACHINES OPERATING WITHCONTINUOUS CURRENT.

APPLICATION FILED JAN-13,1917.

1 ,428,262, Patented Sept. 5, 1922 Patented Sept. I922. A I I I I IUNITED STATES PATENT OFFICE.

EDMUND SCHRODER, OE BERLIN, GERMANY, ASSIGNOR, BY MESNE ASSIGNMENTS, TOTHE CHEMICAL FOUNDATION, INC, A CORPORATION OF DELAWARE.

METHOD OF WORKING ELECTRIC RESISTANCE WELDING MACHINES OPERATING WITHCONTINUOUS CURRENT. 1

Application filed January 13, 1917. ,Serial No. 142,235.

To all whom it may concern: L Wire 10. The secondary of the transformerBe it known that I, EDMUND SCHRODER, a is connected directly with theelectrodes 856 subject of the German Emperor, and resiand 8', whichserve to make the weld bedent of Berlin, in the German Em ire, havetween the plates of metal 9 aud t), for ex- 6 invented a' new andImproved ethod of ample. I

lVorki Electric Resistance Welding Ma- The interrupter is mounted upon ashaft chines perating with Continuous Current, v3, which is inmechanicalcontact with suiti of which the following is-a specification. abledriving means, said driving means he- Heretofore it has been customaryto feed ing capable of regulation in order that the 10 transformers fromcontinuous current mains current pulses per unit of time may be vabysubdividing this, current into single ried at will. Upon the peripheryof the rorushes by means of a suitably constructed 'tating drum areplaced the plurality of coninterrupter, especially of the hammer type.ducting protuberances 4 already referred to,

But interrupters of this kind are not emand which may, as before stated,be insu- 15 ployable where the current is ofrather great lated by anatmosphere of gas. These prostrength, such, for instance, as isnecessary tuberances, by intermittently contacting for the operation ofresistance welding mawith an opposed protuberance 6 carried by chines.In such cases. it is practically iman arm 5, occasion a very abrupt riseof the possible to operate the interrupter without current from zero tothe maximum, and then 20 sparks. In the resistance welding process anequally abrupt fall from the maximum to it is particularly important tohave-an aczero, thus obviating burning the metal becurately' workinginterrupter, because the ing welded and setting up an intense current 7work must be done very often by unskilled quickly and with minimumlosses. hands. The almost instantaneous rise of the our- 85 My inventionconsists in maki use, in rent to its maximum intensity and its abruptconnection with theelectric resistance weldfall to zero is 'shown by thegraph comprising process, of the known property of such in Fig. 2. Iinterrupters as, for instance, gas-filled inlany of the disadvantages ofthe method terrupters of the turbine type, or interrupas hithertopracticed are obviated by the 30 't'ers of the Simon type, to interruptvcurrents above-described improvement There are of considerable strengthwithout the prono greatno-load losses caused by sets of con- .duction ofsparks even in uninterrupted se'rverters, far less space is required,and the vice. The interrupters are employed, accost of the plant is.greatly reduced by subcording to v y invention, for directlyfeedstituting comparatively cheap and light in- 35 ing the transformers.terrupters for the expensive and heavy con- The accompanying drawingshows, dia-- verters. grammatically, an illustrative. embodiment It mustbe admitted that the serviceableof my invention, by means of which theness of the interrupters in their usual form method may be performed;and therein I of construction is limited, but any demand 40 Figure 1 isa diagrammatic view showing with respect to strength of the current andin complete assembly the various parts and complete avoidance of sparksmay be met connections comprising said embodiment; either by couplingtwo or more interrupters and t in parallel (electrically ormechanically), by

Figure 2 is a aphical representation of employing a single interrupterwith a plu- 46 the. induced wel ing. current. rality of nozzles, or,finally, by coupling two In accordance with' the foregoing embodior moreinterrupters of the ast mentioned ment of my invention, a source ofelectrical typp. energy 1 is directly connected to the primary aving nowdescribed my invention, what of the welding transformer 7 through anin-'v I desire to secure by a patent of the United .80 terrupter 2,which may be of the turbine States is:

type, the periphery of which carries a plu- 1. An electric resistancewelding system rality of conducting protuberances 4 which utilizingcontinuous current,compr1s1ng an "are connected by conductors to themain lead interrupter positioned directly between the source ofelectrical energy and the welding transformer, said interrupter beingadapted to operate substantially without sparks.

2. An electric resistance welding system utilizing continuous current,comprising a plurality of interrupter-s adapted to operate substantiallywithout sparks, said interruptters being coupled in parallel andpositioned ing protuberances said interrupter being positioned directlybetween the source of electrical energy and the welding transformer.

An electric resistance welding syste utilizing continuous current,comprising a plurality of interrupters coupled in parallel,

each of said interrupters having a pluralityv of conductingprotuberances, said interrupter being positioned directly between thesource of electrical energy and the welding transformer.

In witness whereof I have hereunto signed my name this twenty-fifth dayof October 1916, in the presence of two subscribing witnesses.

EDMUND SCHRODER.

Vitnesses HENRY HARPER, ALLEN F. JENNYS.

